Welcome to JOF
Could you clarify the model of Jayco referenced, I can't seem to locate a "14SO".
I would first check your owners manual in the Towing section, check for any towing restrictions (i.e.; WDH's, etc.). Some vehicles do to frame design are not conducive to WDH usage. Also, please note that a WDH (Weight Distribution Hitch) isn't a sway device, it's main function is to distribute weight.
If you are inquiring about anti-sway devices, then yes, I would recommend the use of a sway control device with every RV trailer.
Please confirm the new Jayco model number, it will help with responses.
Thanks in advance.